/*
** $Id: lobject.c,v 2.22 2006/02/10 17:43:52 roberto Exp $
** Some generic functions over Lua objects
** See Copyright Notice in lua.h
*/

#include <ctype.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define lobject_c
#define LUA_CORE

#include "lua.h"

#include "ldo.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
#include "lstring.h"
#include "lvm.h"



const TValue luaO_nilobject_ = {{NULL}, LUA_TNIL};


/*
** converts an integer to a "floating point byte", represented as
** (eeeeexxx), where the real value is (1xxx) * 2^(eeeee - 1) if
** eeeee != 0 and (xxx) otherwise.
*/
int luaO_int2fb (unsigned int x)
{
	int e = 0;  /* expoent */
	while (x >= 16) {
		x = (x+1) >> 1;
		e++;
	}
	if (x < 8) return x;
	else return ((e+1) << 3) | (cast_int(x) - 8);
}


/* converts back */
int luaO_fb2int (int x)
{
	int e = (x >> 3) & 31;
	if (e == 0) return x;
	else return ((x & 7)+8) << (e - 1);
}


int luaO_log2 (unsigned int x) 
{
	static const lu_byte log_2[256] = 
	{
		0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
		6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
		7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
		7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
		8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
		8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
		8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
		8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8
	};
	int l = -1;
	while (x >= 256)
	{ 
		l += 8;
		x >>= 8;
	}
	return l + log_2[x];

}


int luaO_rawequalObj (const TValue *t1, const TValue *t2) 
{
	if (ttype(t1) != ttype(t2)) return 0;
	else switch (ttype(t1)) 
	{
	case LUA_TNIL:
		return 1;
	case LUA_TNUMBER:
		return luai_numeq(nvalue(t1), nvalue(t2));
	case LUA_TBOOLEAN:
		return bvalue(t1) == bvalue(t2);  /* boolean true must be 1 !! */
	case LUA_TLIGHTUSERDATA:
		return pvalue(t1) == pvalue(t2);
	default:
		lua_assert(iscollectable(t1));
		return gcvalue(t1) == gcvalue(t2);
	}
}


int luaO_str2d (const char *s, lua_Number *result)
{
	char *endptr;
	*result = lua_str2number(s, &endptr);
	if (endptr == s) 
		return 0;  /* conversion failed */
	if (*endptr == 'x' || *endptr == 'X')  /* maybe an hexadecimal constant? */
		*result = cast_num(strtoul(s, &endptr, 16));
	if (*endptr == '\0') 
		return 1;  /* most common case */
	while (isspace(cast(unsigned char, *endptr))) endptr++;
	if (*endptr != '\0') 
		return 0;  /* invalid trailing characters? */
	return 1;
}



static void pushstr (lua_State *L, const char *str) 
{
	setsvalue2s(L, L->top, luaS_new(L, str));
	incr_top(L);
}


/* this function handles only `%d', `%c', %f, %p, and `%s' formats */
const char *luaO_pushvfstring (lua_State *L, const char *fmt, va_list argp) 
{
	int n = 1;
	pushstr(L, "");
	for (;;)
	{
		const char *e = strchr(fmt, '%');
		if (e == NULL) break;
		setsvalue2s(L, L->top, luaS_newlstr(L, fmt, e-fmt));
		incr_top(L);
		switch (*(e+1))
		{
		case 's':
			{
				const char *s = va_arg(argp, char *);
				if (s == NULL) s = "(null)";
				pushstr(L, s);
				break;
			}
		case 'c': 
			{
				char buff[2];
				buff[0] = cast(char, va_arg(argp, int));
				buff[1] = '\0';
				pushstr(L, buff);
				break;
			}
		case 'd': 
			{
				setnvalue(L->top, cast_num(va_arg(argp, int)));
				incr_top(L);
				break;
			}
		case 'f': 
			{
				setnvalue(L->top, cast_num(va_arg(argp, l_uacNumber)));
				incr_top(L);
				break;
			}
		case 'p':
			{
				char buff[4*sizeof(void *) + 8]; /* should be enough space for a `%p' */
				sprintf(buff, "%p", va_arg(argp, void *));
				pushstr(L, buff);
				break;
			}
		case '%': 
			{
				pushstr(L, "%");
				break;
			}
		default: 
			{
				char buff[3];
				buff[0] = '%';
				buff[1] = *(e+1);
				buff[2] = '\0';
				pushstr(L, buff);
				break;
			}
		}
		n += 2;
		fmt = e+2;
	}
	pushstr(L, fmt);
	luaV_concat(L, n+1, cast_int(L->top - L->base) - 1);
	L->top -= n;
	return svalue(L->top - 1);
}


const char *luaO_pushfstring (lua_State *L, const char *fmt, ...)
{
	const char *msg;
	va_list argp;
	va_start(argp, fmt);
	msg = luaO_pushvfstring(L, fmt, argp);
	va_end(argp);
	return msg;
}


void luaO_chunkid (char *out, const char *source, size_t bufflen) 
{
	if (*source == '=')
	{
		strncpy(out, source+1, bufflen);  /* remove first char */
		out[bufflen-1] = '\0';  /* ensures null termination */
	}
	else	/* out = "source", or "...source" */
	{  
		if (*source == '@') 
		{
			size_t l;
			source++;  /* skip the `@' */
			bufflen -= sizeof(" '...' ");
			l = strlen(source);
			strcpy(out, "");
			if (l > bufflen) 
			{
				source += (l-bufflen);  /* get last part of file name */
				strcat(out, "...");
			}
			strcat(out, source);
		}
		else		/* out = [string "string"] */
		{  
			size_t len = strcspn(source, "\n\r");  /* stop at first newline */
			bufflen -= sizeof(" [string \"...\"] ");
			if (len > bufflen) len = bufflen;
			strcpy(out, "[string \"");
			if (source[len] != '\0')	 /* must truncate? */
			{ 
				strncat(out, source, len);
				strcat(out, "...");
			}
			else
				strcat(out, source);
			strcat(out, "\"]");
		}
	}
}
